JPH0343655A - Fuel tank device - Google Patents

Abstract

PURPOSE:To improve high temperature restarting property by providing a stock tank communicated to a sub-tank in a fuel tank on a return pipe for returning an excess fuel from an engine to the fuel tank, and storing the fuel having a low containing ratio of low-boiling point component. CONSTITUTION:A sub-tank 4 is provided in the inside of a fuel tank 2. A communicating pipe 6 for introducing a fuel in its outside into the inside is arranged on the bottom part of the sub-tank 4. A fuel pump 8 is provided on a bracket 7 fixed to a cap 3 covering the opening part 2a of the fuel tank 2 through a buffer material 9, and installed in the inside of the sub tank 4. A return pipe 14 for returning an excess fuel of an engine into the fuel tank 2 is provided above the sub-tank 4 in the inside of the fuel tank 2. A stock tank 16 having an outlet port 18 and a bent port 22 is provided on the end part of the return pipe 14 to store the excess fuel having a low containing ratio of low-boiling point component.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel tank device used in automobiles and the like.

[Prior Art 1] This type of fuel tank device includes the one shown in FIGS. 10 and 11.

That is, a sub-tank 4 is provided within the fuel tank 2 in order to efficiently use the fuel within the fuel tank 2. A communicating vibro is attached near the bottom of the sub-tank 4 to allow the fuel in the fuel tank 2 to flow into the sub-tank 4.

A fuel pump 8 for pumping fuel to an engine (not shown) is installed in the sub-tank 4, and its suction nozzle 10 is placed at the bottom of the sub-tank 4. Note that a filter 12 is attached to the suction nozzle 10. On the other hand, a return pipe 14 for returning surplus fuel not consumed by the engine to the fuel tank 2 is also opened in the sub-tank 4.

According to the fuel tank device configured as described above, when the engine is operating, the fuel in the sub-tank 4 is sucked in by the fuel pump 8 and sent to the engine side, while all the excess fuel returned from the engine side is Returned to sub tank 4.

'By the way, since this surplus fuel has been heated once on the engine side, most of the low boiling point components have been volatilized, and the content of the low boiling point components is low. Therefore, according to the above configuration, the content of low boiling point components in the fuel in the sub-tank 4 is low. Therefore, during engine operation, the fuel sucked into the fuel pump 8 also has a low content of low boiling point components, and the amount of vapor generated within the pump 8 is suppressed to a low level, thereby suppressing a decrease in the performance of the fuel pump 8. .

In addition, as a prior art document of this invention, Utility Model Application Publication No. 54-
There are No. 92214, No. 60-165218, and No. 61-24225@.

[Problem to be Solved by the Invention 1] However, once the engine is stopped (and the operation of the fuel pump is also stopped at the same time), there is no surplus fuel supplied to the sub-tank. The fuel in the tank flows into the sub-tank through the communication vibe, and the content of low-boiling components contained in the fuel in the sub-tank increases significantly.

In this state, when an attempt is made to restart the engine, if the fuel pump has not been cooled down, low boiling point components in the fuel evaporate at the inlet of the fuel pump, producing vapor. As a result, performance may deteriorate, such as the fuel pump idling, and the engine may become unable to restart.

In other words, if the content of low-boiling components in the fuel in the sub-tank is high, the high-temperature restartability of the engine is reduced.

[Means for Solving the Problems] The present invention provides a sub-tank within a fuel tank, forms a communication passage into the sub-tank through which fuel in the fuel tank can flow, and places a suction nozzle of a fuel pump within the sub-tank. In the arranged fuel tank device, a storage tank for storing surplus fuel is attached to the return pipe for returning surplus fuel to the fuel tank, and this storage tank is provided with an opening that leads to the sub-tank.

[Function 1] According to the above configuration, surplus fuel with a low content of low boiling point components is stored in the storage tank while the vehicle is running. Therefore, even after the engine is stopped, the stored surplus fuel can be supplied into the sub-tank.

[Embodiment] Next, an embodiment of the fuel tank device d of the present invention will be described based on FIGS. 1 to 9.

First, a first example will be described.

In Figures 1 and 2, there is a sub-tank 4 inside the fuel tank 2.
is provided. A communicating vibro is attached near the bottom of the sub-tank 4 to allow fuel from outside the sub-tank 4 to flow into the sub-tank 4. Note that it is desirable that the depth of the sub-tank 4 be as deep as possible.

A fuel pump 8 for pressure-feeding fuel to the engine (not shown) side is attached to a bracket 7 fixed to a lid 3 covering an opening 2a of the fuel tank 2 via a buffer material 9, and is installed inside the sub-tank 4. ing. A suction nozzle 10 of the fuel pump 8 is arranged at the bottom of the sub-tank 4. Note that a filter 12 is attached to the suction nozzle 10.

On the other hand, a return pipe 14 for returning surplus fuel not consumed by the engine to the fuel tank 2 is led into the fuel tank 2 above the sub-tank 4, and an Ia storage tank 16 is attached to the end of the return pipe 14. There is. The storage tank 16 is suspended within the sub-tank 4 via a bracket 17 fixed to the lid 3 covering the opening 2a of the fuel tank 2, and is positioned above the sub-tank 4.

As shown in FIG. 2, the V4 storage tank 16 has an outlet boat (opening) 18 at its lower end, and the storage tank 16 also has a drain boat 20 at the top of its side wall. The discharge capacity of the outlet boat 18 per unit time is set to be smaller than the inflow of surplus fuel per unit time, and the discharge capacity of the drain boat 20 is set to be larger than that of the surplus fuel.
A plurality of bent boats 22 are formed on the wall of the -E section.

Next, the operation and effects of the fuel tank device configured as described above will be explained.

When the engine is in operation, fuel in the sub-tank 4 is sucked in by the fuel pump 8 and sent to the engine. On the other hand, the surplus fuel sent from the engine side flows into the first storage tank 16 and is discharged by the action of gravity.It flows out into the sub-tank 4 through the boat 18, and the low-boiling point components of the fuel in the sub-tank 4 content is maintained at a low value. Note that it is also possible to attach a siphon to the outlet boat 18. In this case, since the discharge capacity of the outlet boat 18 is set as described above, surplus fuel will gradually be stored in the storage tank 4. However, since the storage tank 16 is provided with a drain boat 20, the fuel in the storage tank 16 will never exceed a certain level.
Since the excess fuel flowing into the fuel tank 16 has a fairly high temperature, vapor of low boiling point components is generated in the storage tank 16 as well, but this vapor is smoothly exhausted into the fuel tank 2 through the vent boat 22. Therefore, the low boiling point components within the storage tank 16 are effectively evaporated, and the storage tank 16
The content of high-boiling components in the fuel becomes higher.

Here, when the engine is stopped, the operation of the fuel pump 8 is also stopped, so that no surplus fuel is supplied from the engine side, but the surplus fuel stored in the storage tank 16 is continuously supplied to the sub tank 4. supplied within. Therefore, within a certain period of time after the engine is stopped (a period until the fuel in the storage tank 16 is completely discharged), the flow of fuel in the fuel tank 2 into the sub-tank 4 is suppressed, and the fuel in the sub-tank 4 is suppressed. The content of low-boiling components is maintained at a low value as during engine operation.

When restarting the engine, the content of low boiling point components in the fuel grown by the fuel pump 8 is low within the above-mentioned certain period, so even if the fuel pump is in a high temperature state, the content of the low boiling point components in the fuel is low. There is little vapor generation. Therefore, the fuel pump 8 does not idle, and the engine can be restarted smoothly.

Also, if the engine is stopped while the car is tilted,
As shown in FIG. 3, when there is little fuel remaining in the fuel tank 2, the sub-tank 4 immediately after the engine stops
The liquid level of the fuel in the tank deviates as shown by .
The suction nozzle 10 is exposed. However, since both openings of the communication vibro are arranged to face each other across the diagonal line of the bottom wall of the sub-tank 4 shown in FIG. No exchange of fuel occurs. Therefore, the liquid level of the fuel in the sub-tank 4 rises to the position indicated by 8 or B' after a few seconds due to the fuel supplied from the storage tank 16, the suction nozzle 10 is immersed in the fuel, and the fuel pump 8
This makes it possible to inhale fuel. Therefore, according to the above configuration, even when the engine is stopped on a slope or the like, the fuel pump 8 is prevented from idling due to exposure of the intake nozzle 10.

A second example will be explained. Note that this example is the first
Since the basic configuration and operation and effects are the same as those of the embodiment, explanations of parts that do not require further explanation will be omitted.

As clearly shown in Figure 4, outlet bow 1~
18 and the suction nozzle 10 of the fuel pump 8 are connected to the tube 24
are connected via.

With the above configuration, the content of low boiling point components in the fuel sucked by the fuel pump 8 is further reduced, and when the engine is restarted at high temperatures, no vapor is generated inside the fuel pump 8. Furthermore, the engine startability is further improved.

Furthermore, according to the above configuration, when the fuel in the sub-tank 4 is shifted to one side when the fuel in the sub-tank 4 is running on a good curve or during acceleration/deceleration when the remaining amount of fuel in the fuel tank 2 is low, the intake nozzle 10 is Even if exposed, fuel intake is performed in a nearly normal state, preventing engine malfunctions due to inability to supply fuel.

A third example will be explained. Note that this example is the first
Since the basic configuration and operation and effects are the same as those of the embodiment, explanations of parts that do not require further explanation will be omitted.

As shown in FIG. 5, a check valve 28 is attached to a communication hole formed in the lower part of the side wall of the sub-tank 4 instead of the communication vibro. This check valve 28 is opened to allow fuel to flow into the sub-tank 4 when the fuel level in the sub-tank 4 is lower than the fuel level in the fuel tank 2, and is closed in the opposite case. is set to be

According to #I above, after the engine is stopped, the fuel pump 8 stops sucking the fuel in the sub-tank 4, but the supply of fuel from the storage tank 16 to the sub-tank 4 continues, so the amount of fuel in the sub-tank 4 increases. The fuel level becomes higher than the fuel level in the fuel tank 2. As a result, the check valve 28 is closed, and communication between the sub-tank 4 and the fuel tank 2 is completely eliminated.

Therefore, after the engine is stopped, the content of low-boiling components in the fuel in the sub-tank 4 becomes a lower value than when the engine is in operation, and the high-temperature restartability of the engine is further improved. moreover,
Even after the fuel in the storage tank 16 is completely discharged, no exchange of fuel occurs between the sub-tank 4 and the fuel tank 2, so there is also the advantage that good restartability can be obtained at any time.

In addition, since the fuel level in the sub-tank 4 is higher than the fuel level in the fuel tank 2 after the engine is stopped, the suction nozzle 10 of the fuel pump 8 may be exposed when the engine is stopped on a slope, etc. Idling of the fuel pump 8 can be prevented. That is, as shown in Fig. 16, the fuel tank 2
If there are few fuel residues in the sub-tank 4, immediately after the engine stops, the fuel level in the sub-tank 4 will deviate as shown by A or A', and even if the suction nozzle 10 is exposed, the sub-tank will disappear after a few seconds. Since the liquid level of the fuel in the pump 4 rises to B or B-, the suction nozzle 10 is immersed in the fuel, allowing the fuel pump 8 to suck the fuel.

Furthermore, after the engine is stopped, the high-temperature fuel in the sub-tank 4 does not flow into the fuel tank 2 at all, so the temperature of the fuel in the fuel tank 2 does not rise, and vapor generation in the fuel tank 2 is prevented. suppressed. Therefore, the burden on the evaporative canister (not shown) provided in the fuel tank 2 is reduced.

A fourth example will be described. This embodiment is a modification of the third embodiment.

As shown in FIG. 7, a solenoid valve 26 is attached to the communicating vibro. This solenoid valve 26 is connected to the fuel pump 8 and is set to be open when the fuel pump 8 is operating (engine operating) and closed when the fuel pump 8 is stopped. There is.

According to the above configuration, after the engine is stopped, communication between the sub-tank 4 and the fuel tank 2 is completely eliminated, and fuel is supplied to the sub-tank 4 from the storage tank 16, but fuel flows out from the sub-tank 4. There's nothing to do.

In this embodiment as well, the same effects as in the third Jinoura example can be obtained.

A fifth example will be explained.

Since this embodiment is a modification of the second embodiment, only the different points will be explained.

As shown in Figures 8 and 9, Arara 1 - Retsu 1 - Boat 18
and the filter 12 that covers the suction nozzle 10 are connected to the tube 24.
are connected via. A solenoid valve 30 is attached to this tube 24. This solenoid valve 30 uses a power source common to that of the fuel pump 8 and is connected to the fuel pump 8 via a flow-me switch 32 attached to the filter 12 . Float switch 3
2 is a flow 1-34 immersed in fuel in sub tank 4
It is set to turn on when the float 34 falls below a set level as the fuel level falls, allowing the electromagnetic valve 30 to be energized and listening to the electromagnetic valve 30.

Therefore, the solenoid valve 30 is opened only when the fuel level falls below a set value when the engine is operating, and is normally closed when the engine is stopped. In this case, the setting position of the float 34, which is the reference for turning the foot switch 32 ON-OFF, is set at a level slightly (several IuR) higher than the liquid level at which the opening of the suction nozzle 10 is exposed. This is the corresponding position. In this embodiment, the discharge capacity of the outlet boat 18 can be set to be sufficiently large.

According to the above configuration, when the fuel level in the subtank 4 falls below the set level, the fuel in the storage tank 16 is quickly supplied to the subtank 4, so that the fuel pump 8 due to insufficient fuel supply Idling is prevented.

In addition, under high temperature conditions after the engine has stopped, vapor accumulates in the filter 12, and this vapor pressure lowers the liquid level in the filter 12, so if you try to restart the engine under this condition, , float switch 32
is turned on, and the solenoid valve 30 is closed. As a result, the fuel with a low content of low boiling point components in the storage tank 16 is quickly supplied into the subtank 4, and good engine restartability is achieved.
1 will be given.

Note that the float switch 32 may be eliminated, and the solenoid valve 30 may be directly connected to and interlocked with the fuel pump 8. In this case, it is necessary to set the discharge capacity of the outlet boat 18 to be the same as in the second embodiment. Furthermore, the float 34 of the float switch 32 is connected to the filter 1 as necessary.
It is also possible to arrange it outside of 2.

[Effects of the Invention] According to the present invention, surplus fuel with a low content of low boiling point components is stored in a storage tank while the vehicle is running, and the fuel in this storage tank can be used when restarting the engine. Therefore, during the 8-warm start, the engine is in J3, and the generation of vapor due to evaporation of low-boiling components is suppressed, the fuel pump is prevented from idling, and the high-temperature restartability of the engine is improved.

[Brief explanation of drawings]

1 to 9 show embodiments of the present invention, FIG. 1 is a sectional view of the fuel tank device d in the first embodiment, FIG. 2 is an enlarged sectional view of the storage tank, and FIG. 3 is in a tilted state. 4 is a sectional view of the fuel tank device in the second embodiment, FIG. 5 is a sectional view of the fuel tank device in the third embodiment, and FIG. 6 is a sectional view of the fuel tank device in the tilted state. 7 is a sectional view of a fuel tank device in a fourth embodiment, FIG. 8 is a partial sectional view of a fuel tank device in a fifth embodiment, and FIG. 9 is an enlarged sectional view of a storage tank. It is a diagram. 10 and 11 show a conventional example, and FIG. 10 is a partial sectional view of the fuel tank assembly d, and FIG. 11 is a plan view of the sub-tank. 2...Fuel tank 4...Sub-tank 6 ...Communication vibe 8...Fuel cylinder 1 10...Suction nozzle 14...Return pipe 16...Storage tank 18...Outlet boat

Claims (1)

[Claims] In a fuel tank device in which a sub-tank is provided in the fuel tank, a communication path is formed in the sub-tank through which the fuel in the fuel tank can flow, and a suction nozzle of a fuel pump is arranged in the sub-tank, excess fuel is transferred to the fuel tank. A fuel tank device in which a storage tank is attached to the return pipe to store surplus fuel, and this storage tank has an opening that leads to a sub-tank.